1 /* 2 * Cryptographic scatter and gather helpers. 3 * 4 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 5 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com> 6 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com> 7 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the Free 11 * Software Foundation; either version 2 of the License, or (at your option) 12 * any later version. 13 * 14 */ 15 16 #ifndef _CRYPTO_SCATTERWALK_H 17 #define _CRYPTO_SCATTERWALK_H 18 19 #include <asm/kmap_types.h> 20 #include <crypto/algapi.h> 21 #include <linux/hardirq.h> 22 #include <linux/highmem.h> 23 #include <linux/kernel.h> 24 #include <linux/mm.h> 25 #include <linux/scatterlist.h> 26 #include <linux/sched.h> 27 28 static inline enum km_type crypto_kmap_type(int out) 29 { 30 enum km_type type; 31 32 if (in_softirq()) 33 type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0; 34 else 35 type = out * (KM_USER1 - KM_USER0) + KM_USER0; 36 37 return type; 38 } 39 40 static inline void *crypto_kmap(struct page *page, int out) 41 { 42 return kmap_atomic(page, crypto_kmap_type(out)); 43 } 44 45 static inline void crypto_kunmap(void *vaddr, int out) 46 { 47 kunmap_atomic(vaddr, crypto_kmap_type(out)); 48 } 49 50 static inline void crypto_yield(u32 flags) 51 { 52 if (flags & CRYPTO_TFM_REQ_MAY_SLEEP) 53 cond_resched(); 54 } 55 56 static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num, 57 struct scatterlist *sg2) 58 { 59 sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0); 60 sg1[num - 1].page_link &= ~0x02; 61 } 62 63 static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg) 64 { 65 if (sg_is_last(sg)) 66 return NULL; 67 68 return (++sg)->length ? sg : (void *)sg_page(sg); 69 } 70 71 static inline void scatterwalk_crypto_chain(struct scatterlist *head, 72 struct scatterlist *sg, 73 int chain, int num) 74 { 75 if (chain) { 76 head->length += sg->length; 77 sg = scatterwalk_sg_next(sg); 78 } 79 80 if (sg) 81 scatterwalk_sg_chain(head, num, sg); 82 else 83 sg_mark_end(head); 84 } 85 86 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in, 87 struct scatter_walk *walk_out) 88 { 89 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) + 90 (int)(walk_in->offset - walk_out->offset)); 91 } 92 93 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) 94 { 95 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; 96 unsigned int len_this_page = offset_in_page(~walk->offset) + 1; 97 return len_this_page > len ? len : len_this_page; 98 } 99 100 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk, 101 unsigned int nbytes) 102 { 103 unsigned int len_this_page = scatterwalk_pagelen(walk); 104 return nbytes > len_this_page ? len_this_page : nbytes; 105 } 106 107 static inline void scatterwalk_advance(struct scatter_walk *walk, 108 unsigned int nbytes) 109 { 110 walk->offset += nbytes; 111 } 112 113 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk, 114 unsigned int alignmask) 115 { 116 return !(walk->offset & alignmask); 117 } 118 119 static inline struct page *scatterwalk_page(struct scatter_walk *walk) 120 { 121 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT); 122 } 123 124 static inline void scatterwalk_unmap(void *vaddr, int out) 125 { 126 crypto_kunmap(vaddr, out); 127 } 128 129 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg); 130 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, 131 size_t nbytes, int out); 132 void *scatterwalk_map(struct scatter_walk *walk, int out); 133 void scatterwalk_done(struct scatter_walk *walk, int out, int more); 134 135 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, 136 unsigned int start, unsigned int nbytes, int out); 137 138 #endif /* _CRYPTO_SCATTERWALK_H */ 139